Spark-gap.



J. D. ROBERTSON.

SPARK GAR.

APPLICATION FILED 11011.30, 1910.

. Patented 001211911.

WITNESEEEZ' ww/u. (5 7%M' ran srariis Parana JAMES D. ROBERTSON, OF TOLEDO, OHIO, ASSIGNOR T0 CHAMPION SPARK PLUG COMPANY, OF TOLEDO, OHIO, A CORPORATION (3F MASSACHUSETTS.

SPARK-GAIL,

Specification of Letters Patent.

Patented Get. 2i, ieii.

Application filed November 30, 1910. Serial No. 594,920.

To all whom it may 00mm.-

Be it known that I, JAMES D. Ronsnrson, a citizen of the United States, and a residentof Toledo, in the county of Lucas and State of'Ohio, haveinvented a certain new and useful Spark-Gap; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the figures of reference marked thereon, which form a part of this specification.

My invention relates to devices employed more particularly in connection with the ignition systems pf internal combustion engines for detecting defects in the ignition, butis not restricted to such use as it may be used in any conriection for which it may be adapted or appropriate. Several forms of devices of this character have been used, but none of the same, so far as I am aware, has been. capable of adjustment by hand to vary the distance or gap between the points or electrodes while the engine is running or a current is passing through the-ignition circuit. It is of very great ad vantage when testing out the spark to be able to adjust the gap or distance between the electrodes during a running' 'of the engine for reasons apparent, but owing to the high tension flowing therethrough this has been impossible with the types of gaps heretofore used, as a person in taking hold of the adjusting parts :gwill receive a severe shock even though the part which he grasps is apparently insulated from the circuit parts.

The object of my invention is the provision of a device of the character described, which is capable of being easily adjusted to vary the distance of the visible spark gap during a running of the engine without danger'of shock to the person adjusting the same and which is etlicient in'its operation, and cheap and simple in its construction and manufacture, thus materially enhancing the practicability and of such devices,

The invention is fully described in the following fication, and while, in its broader aspect, capable of embodiment commercial value A in numerous forms a preferred embodiment thereoi is illustrated in the accompanying drawings, in which,

Figure l is an elevation of a spark comprising my invention, Fig. View thereof, and Fig. 3 tudinal section or". the same.

Referring to the drawings, 1 designates the barrel or holder of the gap one end of which is closed and preferably at 2, while the other end thereof is open, as at 8. The closed end 2 of the barrel lis axially bored to permit the projection of a point or electrode 1 therethrough. This electrode is shouldered adjacent its inner end, as at 5, to bear against the marginal edge of said bore at the inner end thereof to limit the outward movement of the elecgap is an end a central longn electrode is threaded to receive a nut ,6 which is adapted to bear againstthe outer closed end of the barrel. and to cooperate with the shoulder 5 to rigidly secure the electrode l in position therein. A jam nut 7 is also shown as being threaded on the outer end of the electrode 4 and in addition to locking the nut 5 against movement, serves as a stud with which a clamp may be removably engaged.

The open end 3 of the barrel 1 has a plug S of suitable conductive material. threaded therein and pro fided at its outer end with a terminal clamp 9 of any suitable form. The other electrode 10 of the device is car- ...ried by the inner endjec'ts within the barrel 1 to a"point adja cent the inner end of the trode i, the gap or distance between such electrodes being varied as desired by a rel ativeturning of the barrel 1 and plug The barrel-1 has a plurality of sight oped ings 11 provided therein in register witlrihe points of the electrodes 4 and 10 to make visible a spark'passing between said elec- .the barrel. 1 around the electrodes to'insulate the vision openings 11 from the iuterior of the barrel, and this tube is h *hl in position within the barrel by a coih pression spring 13, which ..as its 0 ends thrustagainst the adjacent said tube and the plug terminalv i of the plug 8 and pro-.

companion elccenlarged, as

trodes. Aglass tube 12 is inserted with n 7 In the use of my improved device,a per son, to detect a defect in the ignition of an engine, places the device in the ignition circuit as by thereof to the exposed end of a spark plug and engaging the terminal wire for such plug to the end 7 of the device, as is apparent. Upon a starting of the engine, the ignition circuit, of course, being closed,'the operator can see the spark by viewing the same tliroughthe sight openings 11 on the device, and can determine the strength or intensity thereofor detect a defect in the Copies of this patent may be ignition circuit by grasping and turning the barrel 1 for such purpose, as the turning of such barrel, the plug 8 being fixed due to its connection with the spark plug, causes a movement ofthe electrodes 4; and 10 toward or away from each other as may be desired, thus varying the visible spark gap.

The enlarged end 2' of the barrel provides a I wish it understood that my invention is not limited to any specific construction or arrangement of the parts except in so far as such limitations are specifiedin the claims. Having thus descr bed my 1I1V8I1t10n, what connecting the terminal end 9,

ffitted within the barrel obtained for five cents each, by addressing the Washington, D. C.

' 'I claim as newla'nd desire'to secure by Letters Patent, is,--

1. A device of the class described, com

prising a barrel of non-conductive material,

said barrel having one end open and one end closed end of the barrel and having its inner end projecting within the barrel, a.- plug threaded into the open end of the barrel, a terminal clamp projecting from the outer end of, said plug, said plug and terminal clamp being of conductive material and a movable electrode the inner end ofsaidplug within the barrel and adjustable relative to the fixed electrode by a relative turning and plug.

2. A device ofthe class described, comprising a barrel .of non-conductive material, said barrel having 'si it openings therein, a fixed electrode secured to one end of said barrel and projecting therein, electrode threaded within the opposite end closed, a fixed electrode carried by the i fixedly projecting from of said barrel i a movable of said barrel and adjustable relative to the fixed electrode by a turning of the barrel on r a transparent tube around the electrodes, and yielding means. coac-ting with a part of the movable electrode and with said the movable electrode,

barrel, substantially; as described.

tube to retain the latter seated within the In testimonywhereof, I have hereuntosigned my name to-this specification in the presence ,of two subscribing witnesses.

JAMES J). BOBEBTSON.

' Witnesses: I C. W. Owam. M. G: GAsimi Commissioner of Patents, 

